Small to medium-sized beetles, sometimes found on flowers. Many have fan-like (flabellate) antennae, esp. males. Abdomen blunt. Tarsal formula 5-5-4.

Genera of our fauna are rather easy to tell apart based on appearance; species identification of Ripiphorus may be extremely difficult even with specimens in hand.

In the east, Macrosiagon are usually black and red to yellow, ca. 9 mm, with elytra almost covering abdomen, and scutellum covered by pronotum; Rhipiphorus have very short elytra and are smaller, ~4-6 mm; and Pelecotoma flavipes (4-5 mm) has full-length elytra and is piceous-black with yellowish appendages(9)

Worldwide and throughout much of NA, more diverse towards the south; in our area, Ripiphorus and Macrosiagon are widespread, Pelecotoma ranges throughout ne. US and adjacent Canada, 2 genera are restricted to sw. US (OK-TX-AZ), and one to FL)(1)

Hypermetamorphic; bee/wasp parasites lay eggs on/near flowers, sometimes inside flower buds. Larvae attach to visiting bees and are taken back to nest, where they are internal parasites of larval hymenoptera, in some cases only in early stages. Some are reported to feed on leaves in later stages. Adults are short-lived.(13)(14)(15)

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